The business, which was previously split between WPP's Rainey Kelly Campbell Roalfe/Y&R in Europe and Ogilvy & Mather in US, will be moved into one of Omnicom's agencies in New York.
The global business-to-business account involves promoting BT's products and b2b solutions in multiple markets. RKCR /Y&R's grip on BT's UK business-to-business account is understood to be unaffected by the move.
The decision follows last week's news that BT had moved its £55 million media planning business out of its in-house media department and into WPP's Mediaedge:cia.
The telecoms giant moved the account in-house in August 2006 when it terminated its contract with PHD over conflict with Yell and Pipex.
In the UK, Omnicom's Abbott Mead Vickers BBDO handles the consumer advertising account.
RKCR/Y&R picked up the business-to-business account in February 2006 following a final shoot-out against McCann Erickson.
The company's most recent UK work for the client was a high-profile campaign starring Gordon Ramsey.
The ads saw the foul-mouthed chef disrupting his restaurant's staff and customers because he was trying to install his BT hardware himself instead of using the business-to-business service.